The aim of this study is to plan a procedure for the production of terpenes from deal. This is in rule a really general aim which will be elaborated farther. The most of import measure in the beginning of a design is to specify the design demands. The needed capacity is 3,2 dozenss dry substance ( Ds ) per hr. Additionally, the deal provender Ds is predetermined at 50 % wt ( e.g. the deal provender contains 50 wt % of H2O ) .
In this study, terpenes are the lone merchandises of involvement. They are frequently produced in the signifier of gum terpentine in the mush and papermaking industry, which will be explained in Chapter 2. This chapter will be devoted to specifying wood, terpenes and gum terpentine, and will discourse the most of import gum terpentine bring forthing procedure ; The kraft ( or sulphate ) pulping procedure. The chapter is concluded by sum uping of import design characteristics and demands that form the footing of the design of the terpene production procedure. Questions that are relevant for the terpene production procedure are:
What is a suited provender ( e.g. type of deal with a high terpene content ) ?
Which processing stairss are required for the extraction of the terpenes?
What are the parametric quantities for these treating stairss ( e.g. temperature, force per unit area etc. )
Chapter 3 will get down with the stuff balances which form the footing of the procedure design and will find the measures of natural stuffs required ( which is deal in this instance ) . Balances over single procedure units set the procedure watercourse flows and composings ( Sinnott. 2005 ) .
Background, Wood, Turpentine and Terpenes
Wood displays a cosmopolitan composing in footings of its major components ; cellulose ( 40-50 % ) , lignin ( 18-35 % ) , hemicelluloses and polyphenols, but has specific species-related constituents which can be polymeric, like poly-isoprene ( natural gum elastic ) , and suberin, or little molecules, like terpenes, steroids etc. ( Belgacem and Gandini. 2008 ) .
Fig. 1 shows a conventional diagram of wood. Sapwood conducts wet, minerals, O, and nitrogen. As the tree grows in diameter, the sapwood cells cease their conductive map and organize the inactive duramen. Mineral sedimentations, gums and rosins in the duramen gives a darker colour than the sapwood ( Wang et al. 2004 ) .
Figure 1: Conventional diagram of wood ( Wang et al. 2004 )
Cellulose dominates the wood composing, although its proportion compared to the other chief constituents can change significantly among different species ( Pettersen. 1984 ) . General chemical analysis on wood distinguishes between hardwoods ( flowering plants ) and deals ( gymnosperms ) , whereas deals are richer in lignins, and hardwoods are richer in hemicelluloses. Typical chemical composings of some wood species are shown in Table 1. Overall, wood has an elemental composing of approximately 50 % C, 6 % H, 44 % O, and hint sums of several metal ions ( Sjostrom. 1993 ) .
Table: Chemical Composition of Different Hardwood Species ( Sjostrom. 1993 )
Scottishs Pine ( Pinus sylvestris )
Spruce ( Picea glauca )
Eculyptus ( Eucalyptus camaldulensis )
Silver Birch ( Betula verrucosa )
– Other polyoses
Softwoods consist chiefly of long ( 3 to 5 millimeter ) cells called tracheids which are about 20 to
80 ten 10-6 m. Hardwoods consist chiefly of two sorts of cells ; wood fibres and vessel elements.
Wood fibres are elongated cells which are similar to tracheids except they are smaller, merely 0.7 to 3 millimeters long and less than 20 ten 10-6 m in diameter, and they do non function for fluid conveyance in the life tree. The vas elements do function for fluid conveyance in the life tree, and they can hold a broad scope of sizes.
Figure: Typical morphology of a wood fiber ( Belgacem and Gandini. 2008 )
Fig. 2 shows the function of the three basic constituents severally as the matrix ( lignin ) , the reinforcing elements ( cellulose fibers ) and the interfacial compatibilizer ( hemicelluloses ) of a wood fibre. The in-between gill ( 0.5-2 I?m ) is chiefly composed of lignin ( 70 per cent ) , associated with little sums of hemicelluloses, pectins and cellulose. The primary wall, frequently difficult to separate from the in-between gill, is really thin ( 30-100 nanometer ) and is composed of lignins ( 50 per cent ) , pectins and hemicelluloses. The secondary wall is the chief portion of the vegetational fibres. It ‘s indispensable constituent is cellulose and it bears three beds, viz. , the external, S1 ( 100-200 nanometer ) , the cardinal S2 ( the thickest bed of 0.5-8 I?m ) and the internal or third bed, S3 ( 70-100 nanometer ) situated close to the lms ( Belgacem and Gandini. 2008 ) .
Terpenes & A ; Turpentine
Table 3: Major groups of terpene compounds
harmonizing to the figure of isoprenic units
First of wholly, this subdivision will get down by explicating what terpenes are. Terpenes refer to a household of of course happening compounds which portion isoprene ( 2-methyl-1,4-butadiene ) as a common C skeleton edifice block. This structural relationship was identified by Wallach in 1887 and led to the ‘isoprene regulation ‘ . Based on this generic regulation, terpenes can be classified harmonizing to the figure of isoprene units ( Table 3 ) .
Figure: Chemical constructions of the most common gum terpentine monoterpene constituents. ( Belgacem and Gandini. 2008 ) .
Turpentine[ 1 ]is the common term given to the volatile fraction isolated from pine rosin which consists chiefly of terpenes ( Definition of gum terpentine in CAS RN 8006-64-2 ) . The terminology for gum terpentine is confounding as gum terpentine is a name applied to legion semi-fluid oleoresins obtained from cone-bearing trees every bit good ( Definition of gum terpentine in CAS RN 9005-90-7 ) .
From the context of most literature considered, the term “ gum ” refers to the oleoresin ( or rosin ) from pine trees.
Distillation of the oleoresin consequences in the volatile gum terpentine oil and resin. Rosin is the toffee, transparent, calendered, faintly aromatic solid that remains one time all the gum terpentine oil has been extracted. Oleoresin obtained from pine trees consists of 75 to 90 per centum rosin and 10 to 25 per centum oil. When distilled, it yields gum terpentine. Turpentine is a mixture of terpenes and indispensable oils, which vary in per centum based on geographic location, tree species, and the distillment procedure. In this study, the gum terpentine definition given by CAS RN 8006-64-2 will be used. Turpentine is frequently classified by its agencies of production ( i.e. , steam-distilled, destructively distilled, sulfate-distilled, or sulfite-distilled gum terpentine ) . There is considerable difference between the types of gum terpentine in production degrees and current usage forms.
Gum liquors of gum terpentine: Liquors of gum terpentine obtained by distillment of oleoresin ( gum ) from populating trees.
Steam-Distilled Wood Turpentine: Liquors of gum terpentine obtained by steam distillment from the margarine pitchy constituent of wood.
Destructively Distilled Turpentine: Liquors of gum terpentine prepared from the distillation obtained in the destructive distillment ( carbonisation ) of wood.
Sulfate Wood Turpentine: Liquors of gum terpentine prepared from condensates that are recovered in the sulfate procedure of cooking wood mush.
The turpentine chemical composing is strongly dependent on the tree species and age, geographic location and the overall process used to insulate it. In gum terpentine produced in the United States, the major components are the volatile terpene hydrocarbons ; I±-pinene ( 75 – 85 % ) , I?-pinene ( up to 3 % ) , camphene ( 4 – 15 % ) , limonene ( dipentene, 5-15 % ) , 3-carene, and terpinolene ( percentages non provided ) ( Chinn. 1989 ) , see Table 4 and Figure 3. Components that are derived from gum terpentine for usage in other merchandises are listed in Table 5.
Table 4: Components ( in weight per centum ) and denseness of sulfate gum terpentine ‘s arising in different states ( Gscheidmeier and Fleig. 1996 )
Spec. Gravity ( g/mL at 20 A°C )
Table 5: U.S. Companies that produce merchandises derived from gum terpentine ( Haneke. 2002 )
vitamin D, l-Limonene
Aldrich Chemical Company, Inc
Bush Boake Allen Inc
Florida Chemical Company, Inc
Florida Chemical Company, Inc
Millennium Specialty Chemicals Inc
Harmonizing to Gscheidmeier and Fleig ( 1996 ) there are five types of gum terpentines ( turpentine oil, steam-distilled gum terpentine, destructively distilled gum terpentine, sulfate-distilled gum terpentine and sulfite-distilled gum terpentine ) , categorized by their starting stuff and production method. Since the last two decennaries, the production of sulfate gum terpentine dominates the entire gum terpentine production ( about 70 % ) and the remainder about entirely as gum gum terpentine ( which is obtained from tapping populating trees ) . This is explained by the high labour costs and/or the demand of specialised equipment associated with the production of other turpentine types.
Annual worldwide production of gum terpentine has been estimated at 330,000 dozenss and 250,000 dozenss for 1995 and 1998, severally ( Coppen and Hone. 1995, Plocek. 1998 ) . 55 % Percentage of the worldwide pulping mills use the sulphate procedure, bring forthing sulfate gum terpentine as a by-product ( Gscheidmeier and Fleig. 1996 ) .
Production of petroleum sulphate gum terpentine is performed at the big paper manufacturers that use the kraft wood pulping procedure. When kraft pulping is carried out continuously, every bit much as 74 % of the original gum terpentine nowadays in the wood can be extracted. Due to the presence of the S compounds, the merchandise has a dark colour and a disgusting olfactory property ( Chinn. 1989 ) . The petroleum sulfate gum terpentine is sold to other companies for farther distillment and purification to obtain constitutional merchandises. In the United States, several companies derive terpenes from sulfate gum terpentine ( see Table 5 ) . The gum terpentine content for Pinus species is highest compared to other tree species, viz. 6-16 kg/T mush compared to 2-3 kg/T mush for fir or spruce trees ( Gscheidmeier and Fleig. 1996 ) .
Turpentine has long been associated with “ naval shops ” , which refers to rosin, gum terpentine, tall oil and more, all produced from pine trees. Turpentine, once the most widely used pigment dilutant, is still employed in pigments ( both family and creative person ) every bit good as in other coatings. The usage of gum terpentine has diminished late due to the handiness of less expensive petroleum-based dissolvers ( Cronin. 1979, Gscheidmeier and Fleig. 1996 ) .
Presently, gum terpentine continues to be used as a dissolver or dilutant for assorted merchandises, such as natural or modified binders, rosins, including alkyd rosins, oils, pigments, and glosss. In oil-based pigment and coating preparations, peroxidation of the terpenes in gum terpentine accelerates the drying of oils and other movie formers.
Even though its usage as a dissolver has decreased, gum terpentine has attracted enormous involvement and usage as a natural stuff for the chemical industry ( Gscheidmeier and Fleig. 1996 ) . In 1988, 209 million lbs of derived functions were produced from sulphate wood gum terpentine ( Chinn. 1989 ) . Terpenes and other compounds derived from gum terpentine are used as natural stuffs or submaterials for merchandises such as tyres, plastics, adhesives, spirits and aromas, cosmetics, pigments, and pharmaceuticals. Separation by process-scale chromatography can give I±-pinene ( pureness up to 99 % ) and I?-pinene, 3-carene, and monocyclics ( I±-terpinene, limonene, and phellandrene ) . Steam distillment of the residue separates out the higher boiling fractions ( terpene intoxicants, sesquiterpenes, and diterpenes ) ( Gscheidmeier and Fleig. 1996 ) . Turpentine derived functions are indispensable ingredients in the industry of aroma chemicals. The value of gum terpentine reflects about 25 % of the value of all aroma chemicals produced both for sale and for internal usage each twelvemonth ( Plocek. 1998 ) . Some of the chemicals derived from gum terpentine along with their utilizations are listed in Table 6.
Table 6: Chemicals derived from gum terpentine and their utilizations
Flavor ingredient, insect attractant
Pharmaceutical, plasticiser, aroma
Esters of pinic acid
Flavor ingredient and aroma aroma
vitamin D, l-Limonene ( Dipentene )
Cleaning agent, dissolver, spirit and aroma additive
Polymerization gas pedal for gum elastic
Solvent, fabric aides, floatation AIDSs, cleansing and disinfecting merchandises
Varnish rosin, melt adhesive
Disinfectant, fabric aides, aroma
Terpenes incorporating S
Lubricating oil additives
Fuel additives, oil field chemicals, aromas
MSDNA & A ; Biodegradability of Turpentine
Turpentine is a natural merchandise and is wholly biodegradable. Below the solubility bounds, gum terpentine does non stand for a jeopardy to biological wastewater-treatment workss ( Gscheidmeier and Fleig. 1996 ) . However, the biological and chemical O demand for gum terpentine is exceptionally high ( Irwin. 1997 ) and hence outflowing discharges are regulated ( 40 CFR 454.22 and 40 CFR 454.32 ) . Environmental releases of gum terpentine may happen at production installations where faulty equipment or spills occur. Facilities are required to utilize best direction patterns ( BMP ) to cut down the sum of gum terpentine released to the air during turpentine production procedures ( 40 CFR 63.446 ; 40 CFR 430.3 ) .
The Clean Air Act of 1990 did non sort terpenes, components of gum terpentine, as air fouling substances. Turpentine released into the environment is wholly degraded by natural procedures within a few yearss. The rate of debasement depends on the concentration of gum terpentine, temperature, handiness of air, and presence of bacteriums. Turpentine has been ranked as holding zero possible as an ozone consuming substance or for planetary heating ( Gscheidmeier and Fleig. 1996 ) .
Background, Processes for Producing Turpentine
The Kraft Procedure
The purpose in chemical pulping is to emancipate the fibers from the wood matrix by delignifying the
wood. A typical kraft procedure strategy is shown in Figure 10. Wood french friess are cooked at an elevated temperature ( 150-180A°C ) in an aqueous digestion spirits ( NaOH, Na2S, Na2CO3, besides called white liqour ) . The Na sulphide in the cookery liquour while the Na hydrated oxide is consumed by reaction with the lignin and saccharides in the wood. The cookery is done in big force per unit area vass at 7-13 saloon, for 1-5 h. There are two chief cookery processs, batch-wise or uninterrupted, utilizing different digesters and equipment. Batch-wise cooking contribute to some advantages like ( Monica et al. 2009 ) :
More flexible production -easy to get down / halt leting stand-by clip -possibility to quick alterations between, different mush qualities or deal / hardwood
More efficient gum terpentine recovery
An ordinary mush factory may be equipped with a set of four digesters or more, with a size of 150-400 M3s each. Once the cookery is complete, the wood is broken down into two stages: a soluble stage incorporating the lignin and alkali-soluble hemicellulose and an indissoluble stage incorporating the alpha cellulose or mush.
In the instance of batch digesters, air trapped with the french friess and gases formed during digestion are relieved intermittently during cooking. In deal pulping, gum terpentine is obtained by venting the digester and so dividing the fibers and black spirits from the H2O and gum terpentine in a cyclone centrifuge. The vapour mixture is so piped to a capacitor and so to a separation armored combat vehicle, where the aqueous and turpentine stages separate due to their denseness difference. The aqueous
underflow is piped away, and the Crude Sulfate Turpentine ( CST ) flood is besides piped off to storage armored combat vehicles. Because of the caustic effects of CST, shrieking and storage armored combat vehicles are made of mild steel, and all other constituents of unstained steel. The assorted non-condensibles ( i.e. unable to be condensed
under the operating conditions used ) are passed to a scouring column where they are cleansed of unwanted compounds by acerb solution ( to organize non-volatile salts ) .
Crude sulfate gum terpentine is condensed from the bluess of wood digestion. Sulfur compounds ( methanethiol, dimethyl sulphide ) are oxidized with Na hypochlorite solution at 60A°C to less volatile sulfonic acids, sulfoxides, or sulfones. These are removed by a assortment of methods. This merchandise has a characteristic musty olfactory property. At the terminal of the cook, the digester contents are transferred to an atmospheric armored combat vehicle, called the blow armored combat vehicle. Gases go forthing the blow armored combat vehicles pass through a capacitor to take wet, and the uncondensed gases are incinerated in a burning device.
Black spirits is spent cooking spirits incorporating the dissolved organic substances and the used inorganic cookery chemicals. In order to transform the inorganic substances back to the active cookery chemicals the black spirits is evaporated and burnt, ensuing in a smelt. After disintegration in H2O, the smelt is turned into green spirits. Causticising converts the green spirits into white spirits.
The grade of delignification is measured by finding the kappa figure of the mush. The
kappa figure value gives an estimation of the lignin content in mush. Lower kappa figure peers
lower sum of lignin in mush. The entire output of the cook is determined as the sum of mush
produced compared to amount of wood charged. The mush viscousness can be related to the grade
of polymerization of the saccharides and can be used to supervise the grade of saccharide
debasement. The lower the viscousness value, the more the saccharides have been degraded ensuing in shorter saccharide concatenation length ( Monica et al. 2009 ) .
A batch-wise production procedure is more suited ( with regard to uninterrupted production ) for turpentine recovery as it is more efficient ( Monica et al. 2009 ) . The most common batch digester in usage is the stationary perpendicular cylinder with a conelike or spherical underside.
Figure 5: Schematical overview of kraft pulping procedure ( Buonicore and Davis. 1992 )
The delignification of wood ( i.e. the remotion of the structural polymer lignin from the wood ) in aqueous alkali returns quickly provided that the cookery spirits besides contains hydrosulphide ions. It was early recognized that the delignification rate increased with the charge of sodium sulfide as shown in Figure 6.
The selectivity of disintegration of saccharides and lignin during a kraft cook returns in three
distinguishable stages with the first one simply being an extraction of both types of constituents ( initial
Figure 6: Dissolution of lignin from spruce wood at a cooking temperature of 160 A°C demoing the influence of sulphide charge ( Hagglund. 1951 ) stage ) . When around 20 % of both saccharides and lignin have gone into solution, the dynamicss
Figure 7: Selectivity in the disintegration of saccharides and lignin on kraft pulping of deal ( Monica et al. 2009 ) alterations dramatically and a instead selective lignin disintegration takes topographic point until about 90 % of all lignin has been dissolved ( bulk stage ) . The concluding part of the lignin can, nevertheless, merely be removed with great trouble and at the disbursal of a big saccharide loss ( concluding stage ) . In pattern, the cook is interrupted at the passage point to the concluding stage in order non to lose in mush quality or output ( Figure 7 ) . The prevailing loss of saccharides in kraft pulping is due to the fact that most of the hemicellulose constituents are degraded and dissolved in the alkaline spirits. Due to the differences in wood morphology and lignin construction, the rate of delignification is higher in hardwood species as compared to softwood ( Monica et al. 2009 ) .
Typical values for the entire alterations in constituent outputs as the consequence of a kraft cook are shown in Table 7 where the big loss of saccharides is farther illustrated.
Table 7: Typical output values ( % on wood ) for the single wood constituents after kraft cookery of pine.
Valuess for wood within brackets ( Monica et al. 2009 )
35 ( 39 )
4 ( 17 )
5 ( 8 )
~0 ( 5 )
3 ( 27 )
& lt ; 0.2 ( 4 )
The delignification chemical science encountered in kraft a pulping has been exhaustively investigated. It has been clearly shown that a atomization of the polymeric lignin and the debut of hydrophilic groups are necessary requirements for the disintegration. The cleavage reactions take topographic point in the prevailing chemical linkage linking the phenylpropane units together, the I?-O-4 linkage. By the action of hydrosulphide ions, the phenolic I?-O-4 constructions are to a big extent fragmented. If no hydrosulphide ions are present, as in sodium carbonate pulping, the delignification efficiency is hapless and the rate of delignification becomes much lower ( Monica et al. 2009 ) . The chemical science of cleavage of phenolic I?-O-4 constructions is shown in Figure 8.
The chemical science of lignin disintegration in a kraft cook is non merely dependant on the cleavage of I?-O-4 constructions. A low H-factor, i.e. a high charge of hydrated oxide and hydrosulphide ions, is good therefore bespeaking that a drawn-out pulping clip, in add-on to an increased grade of I?-O-4 cleavage, besides consequences in an addition of non-desirable reactions able to forestall or to decelerate down the overall lignin disintegration.
As delignification is a really complex topic and the aim of this study is to bring forth gum terpentine ( terpenes ) , the other chemical reactions fall beyond of the range of this study. For an overview of the chemical science in kraft pulping see Monica et Al. 2009.
Figure 8: Chemical reaction strategy for the cleavage of phenolic I?-O-4 constructions in lignin during kraft pulping conditions. Competing reactions are besides indicated in the figure. L denotes a lignin residue ( Monica et al. 2009 )
Design of turpentine recovery procedure
Basic Philosophy Behind the Design
As described in Section 2, the sulphate gum terpentine sums to about 70 per centum of the entire one-year gum terpentine production, and gum gum terpentine ( tapping of life trees ) sums to about 30 per centum. The kraft procedure is a complicated procedure and is designed for the intent of bring forthing mush for paper fabrication, although it does bring forth sulfate gum terpentine as a byproduct. The chief aim for the procedure of tapping of life trees is the production of gum terpentine and extra merchandises ( e.g. resin ) . It is besides a much simpler procedure focused more on the production of gum terpentine. Therefore, utilizing the kraft procedure as a footing for this turpentine production design does non give intent to the mush being produced. And, as the demand for this design is to utilize deal ( and non populating trees! ) as natural stuff, both of the above options for the production of gum terpentine and terpenes seem unviable for the design in this study.
The most obvious pick would hence be to return to the traditional ways of bring forthing gum terpentine, i.e. steam-distilled ( wood ) gum terpentine. In this study, the method for retrieving the gum terpentine will be based on extraction of the merchandises from dead wood and/or waste wood like stumps by utilizing the steam and dissolver procedure which was foremost used in the beginning of the twentieth century ( Palmer. 1934 ) , and this production method peaked in the 60 ‘s and 70 ‘s ( Haneke. 2002 ) .
The steaming portion of the procedure consists of steam being introduced in the underside of the vas that holds the wood french friess, the steam and oil bluess pass out of the top to capacitors, and the condensate runs to automatic gravitation centrifuges. The oils that are recovered in this distillment consist basically of gum terpentine and pine oil, and hence holds the most of the terpenes. Steam-distilled pine oil contains a few per cent of terpene hydrocarbons boiling above gum terpentine but is chiefly third terpene intoxicants, such as alpha-terpineol, and besides contains the secondary terpene intoxicants, fenchol and borneol, together with a little sum of a phenol quintessence, methyl chavicol ( Palmer. 1934 ) .
The following ( optional ) measure is the extraction of the resin from the steamed french friess. The contact with steam serves to heat the wood exhaustively and to pull to the surface a part of the resin, therefore doing it available for easy extraction. The resin consists of different rosin acids, particularly abietic acid. Different types of dissolver are used including naphtha, benzine, methylbenzene, gasolene ( Yaryan. 1909, Sherwood and Cole. 1924, Little. 1930, Black and Minch. 1953 ) .
Design of Procedure
The first measure in the processing is the separation of the majority of the volatile oil nowadays in the wood by agencies of steam distillment. Steam is introduced in the underside of the vas, the steam and oil bluess pass out of the top to capacitors, and the condensate runs to automatic gravitation centrifuges. The proficient control of the procedure begins with the steaming measure. Steam may be either saturated or superheated, and the operation is conducted under low, moderate, or high force per unit area, depending upon the consequences desired. Steaming is continued to a point of steam economic system by finding the proportion of oil to H2O in the distillation.